Science v politics
Marc Sidwell is right to wish for fewer appeals to “consensus” in political life [Let’s agree we’ve had enough of consensus, Friday]. Most political questions are of precisely the kind that do not (and should not) permit consensus. It’s different in science, where “consensus” doesn’t mean passive observance of an agreed party line, but rather, a collective but provisional view about what is currently the best hypothesis to explain natural phenomena – for example, that the solar system is heliocentric and that plate tectonics explains the configuration of the continents. It should not be confused with conservatism – a reluctance to accept new ideas – or biased adherence to a particular theory. Both of the latter played a part in Linus Pauling’s rejection of quasicrystals: Pauling thought he had a better explanation of the experimental results, and he was notoriously dogmatic about his own theories. This year’s chemistry Nobel laureate Dan Shechtman was unfairly criticised for his early claims about quasicrystals, but not for long and not by everyone. Apart from some old and very well-established notions such as those above, consensus is actually rather rare in science. Conservatism is much more common, but that’s the price you pay for a methodology that works so well. Political conservatism can offer no such justification.

Philip Ball, author and science writer, www.philipball.com